30-Bottle Essential Oil Carrying Case for the taller 15ml (1/2 oz) bottles, and also can be used for 30ml (1 oz) bottles up to 4" tall. If you use 15ml-only and no 5ml (1/6 oz) bottles, this is the case you will want, as the 3-inch case gets a bit tight, especially if using the taller, slimmer 15ml bottles that are 2 7/8" in height. Also, if you are searching for a case to hold 1 oz (30ml) bottles, be sure to check your bottle height before ordering. This case will fit some 30ml bottles up to 4 inches in height, however, you may need the 5-inch case available here for taller 30ml bottles.